Biological functions of mouse seminal vesicle fluid. II. Role of water-soluble fraction of seminal vesicle fluid as a nonspecific immunomodulator.

The suppressive mechanisms of T cells induced by water-soluble fraction of mouse seminal vesicle fluid (WSF-SVF) were investigated to clarify its immunological roles in the reproductive immunity. WSF-SVF inhibited the blastogenic responses to concanavalin A (Con A) or phytohemagglutinin (PHA) of T cells. Pretreatment of splenocytes with WSF-SVF did not suppress the blastogenesis of splenocytes to Con A when treated cells were washed before cultures. WSF-SVF did not inhibit the proliferation of Con A-activated splenocytes, that of listeria-immune splenocytes to listeral antigen and growth of tumor cells (Yac 1 cells, Ehrlich ascites carcinoma cells, EL 4 cells). Listerial antigen-specific immune response was not observed when mice were immunized with both listerial antigen and WSF-SVF, whereas it was observed when mice were immunized with only listerial antigen. WSF-SVF also significantly inhibited allogenic MLR. WSF-SVF did not adsorb Con A, and its suppressive activity was rather enhanced by heating at 56 degrees C for 30 min. These results suggest that WSF-SVF inhibits the stage of sensitization of T cells with antigen or stimulant, such as mitogen nonspecifically, without adsorption to antigen or mitogen, and its substance is stable.